1. Field of the Invention
The present invention relates to a data transmission system which enables a data transmission with frame/field accuracy in, such as a video processing system.
2. Description of the Related Art
Usually, a video processing system treating video stream data requires operational accuracy with the frame/field accuracy and conforms to a serial digital interface (SDI: SMPTE-259M specification in Japan) system or a high-definition (HD)-SDI (SMPTE-292M specification in Japan). On the other hand, owing to the development in a data compression transfer technology, a transmission system of the video stream data like moving picture exports group (MPEG) data in a data compression state has been widely used.
However, it is hard for a conventional and general data communication method to communicate with assured time accuracy and need a specific apparatus for communicating with the assured time accuracy. As a result, problems that necessary data may cause delay and that an increase in costs coming from securing a specific communication route and from introducing its specific communicating apparatus have occurred.
For example, when transmitting the MPEG data, the data communication method frequently transmits it by a TCP/IP system, but this TCP/IP system cannot assure the time accuracy of communication and has to be provided with a buffer on a reception side to solve the delay problem. As a result, the TCP/IP system delays time and complicates management.
The conventional data transmission method and its apparatus relating to the present invention are described in Jpn. Pat. Appln. KOKAI Publication No. 2004-166059 and Jpn. Pat. Appln. KOKAI Publication No. 2002-369219.